Mix hamburger, milk, peanut butter and onion soup mix by hand in a bowl
Place hamburger mix on cookie sheet and flatten by hand or with rolling pin filling the whole cookie sheet to the edges
Bake at 350 for ten minutes, and pull out of oven
The meat cake, if you will, has now shrunk. Add chopped onions to the edges and put back in oven for ten minutes
Pull meat cake out again, this time add cheese slices, pickle and scoop onions onto meat. Now place the tops of the slider buns on the meat cake making individual burgers, but don't cut the meat yet. Put bake in oven for 10 minutes
Pull out and use a pizza cutter to cut the meat and scoop onto the bottom buns that did not go in the oven